Mechanism for truing and dressing grinding wheels



March 27, 1928. 1, 3,70

F. J. HOHNHORST ET AL MECHANISM FOR TRUING AND DRESSING GRINDING WHEELS Filed Feb. 16, 1925 s Sheets-Sheet 1 v'ze 2? /NVENTORS.

March 27, 1928.

' F. J. HOHNHORST ET AL MECHANISM FOR TRUING. AND DRESSING GRINDING WHEELS Filed Feb. 16, 1925- s Sheets-Sheet 2 IN VE N TORS Patented Mar. 27, 1928.

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FERDINAND If. nonnnons'r Ann rnanrnann J. xlzonenn, or oovrneron, KENTUCKY.

MECHANISM" roe eme. Ann nnnssme emnmne WHEELS.

Application filed February-'16, 1925. Serial N... 9,412.

Our invention relates to mechanism truing and grinding or polishing surfaces of metal in precision grinding, and isexemplified as em-' ployable for truing or dressing'the grind ing wheel without removing the grinding wheel from the grinding or polishing ma.- chine; r v

'Our invention is an improvement upon the devices shown, described and claimed in our copending' applications for patents on improvements" in mechanism for truing and dressing grinding wheels, respectively filed in the United States Patent Office May 3 1, 192 as Serial No. 717,015, and January 30,

' 1925, as Serial No. 5,707.

that in precision grinding or polishing, it is essential: for'obtaining' best results that the grinding wheel shal be maintained in its true form, for instance, cylindrical form, and that for accomplishing this, it is advisable to employ an abrad ing wheel or abrading wheels loc'atedat an angle with relation .to the plane of 'the grinding wheel, and, when more than one abrading wheel is employed, to locate these at angles with relation to each other, and to mount the abrading wheel jor abrading wheels in such manner that vibrations thereof during the grinding or polishing are avoided, in order that no grooves, ridges or varying surfaces may be imparted to the grinding or polishing surface of the'grind ing wheel by the truing or dressing device. Itisan object of our invention therefore to provide a truing or dressing device of thischaracter.

It is the object of our invention, further,

lVe have found to provide an abrading wheel having ball bearings at the respective sides thereof, and mounted on a stub, shaft or axle, hereinafter called an axle, which is preferably rigidly held, and having supports at'its respective .ends so positioned that the plane of the abrading wheel isat an angle to the plane of the grinding wheel. a

It is the object of our invention, further,

to provide a head and a plurality of axles in said head in non-parallel directions, and rotary abrading wheels about said axles in non-parallel planes, and supports at the respective ends ofsaid axles so as to locate supports at the respective sides of said respective abrading wheels; further, to provide means whereby the axleor axles may be dressing grinding wheels, such as emery wheels employed'in machinery for grinding or polishing.

readily removedfrom and applied to the head, so that the parts may be readily assembled and dissembled for attention and, repairs of the same. v

Theinvention willbefurther readily understoodfrom thefollowing description and".

claim, and from the drawings, in which latter:

Fig. 1 is a plan view of our ilnprovedde. i'lce'applied to an exemplified grinding ma chine, partly broken away. I 1 Fig. .2 is a cross-section of the same, taken on the line 22 of Fig. 1, and partly broken away. 3 Fig. 3 is a plan view of the abrading' wheels and the mounting therefor in a preferred relation to a grinding wheel, the latter partlybroken away.

Fig. 4 18 a verticalv axial section of the same, taken on the line H of Fig. 8-,. and partly broken away;v 1 Fig. 5' is a detail 55-of Fig. 2. e

6 isa' plain view of a modified form of the mounting for the abrading wheel, shown in relation' to' a' grinding wheel, partly broken away. i

Fig. 7 is a vertical axial section of-the same, taken on the line 7'-7 of Fig. 6'; and,

Fig. 8 isa detailin section taken'on the line 88 of Fig.6.

llle have exemplified our invention as employed in connection with a so called grinding or polishing machine employing a rotary grinding wheel 11 for efiect'ing the he work to beground or polished, which may for instance 'be a s l1'aft,is"arranged to be placed between suitable center'sil2, 13, of which 12 may exemplify ahead-center, arranged to be rotated by suitable driving means, as by a pulley 14. A usual quill 15 in which the head-center is supported in usual manner is journaled in a bearing 16 of a headstock-17, slidable'laterally on guideways 18, 19, of a table 20.

The tail-center 13 ismounted in a suitable sleeve-'21, movable axially in a bearing 22,

1n usual manner, the bearing being on a'tailstock 23 laterally adjustable on the guideways 18, 19, of the table 20.

The table is exemplified f as pivotally mounted by a pivot 25 on a saddle 26, which has lateral reciprocating motion impartedby a pinion 2'7, suitably driven, meshing in section on the line thereto by power means, in usual manner, as i fixed to the shaft.

with the T-slot 39 in the frame, and the.

nuts clamping the slide to the frame. The

shaft is rotatable in suitable manner, as by a belt passing about suitable pulleys 40, 41,

In the exemplification, the work located between the centers may be caused to reciprocate axially in planes parallel to the axis of rotation of theigrinding wheel for grinding or polishing straight work, or the table may be adjusted to an angle with relation to said parallelism, effected, for instance, by rotation of the handle as according to the reading on the gage 43.

e haveinthe present exempliiication illustrated a reciprocating table on which to mount the work, the grinding wheel having a stationary position, although the relation of the parts may be reversed, the work being stationarily positioned and the grinding wheel having reciprocations imparted to it. l/Ve have instanced the abrading parts as acting on the grinding wheel in the absence of work bet-ween the centers. The grinding machine may be of any desirable construction.

The rotary abrading parts are exemplified as abrading wheels 45, 145. These abrading wheels are preferably of a texture much harder than the grinding wheel and of smaller diameter than the diameter of the grind ing wheel on which they operate. Both abrading wheels operate on the same grinding Wheel. The rotation imparted to the grinding wheel is instanced as in the direction of the arrow a, while the rotations imparted to the abrading wheels through the medium of the grinding wheel are instanced as in the direction of the arrows b, 0.

The grinding wheel during operation becomes impregnated with particles of dirt or metal from the work being operated on, and becomes comparatively glossy and thereby loses its grinding effect, its granular structure also becoming dull at the grinding face, thereby reducing its grinding or polishing properties. I

By means of our invention, particles of dirt and metal are removed from the grind ing surface of the grinding wheel by coacting rotary abrading parts which act counter to each other or crossingly with relation to each other upon the grinding surface of the grinding wheel, whereby to clear the rerseavos opposite formations of the rotary abrading parts.

'By means of our invention. further, the

rotary abrading parts are located about rigid axles and are caused to rotate in fixed paths for imparting regular and unvar'yingj form to the rinding wheel throughout the grinding sur' ace of the grinding wheel, in order that coaction between all portions of said grinding surface and the work may be equal for imparting regular and unvarying contour and polish to said work.

The swirling actions of the respective rotary abrading parts upon the grinding surface are in opposite directions, so that the swirling action of one of said rotary abrading parts is to draw the dirt or particles of metal out of the interstices or contours in one direction, whereas .the other rotary abrading part acts upon said dirt or particles in the opposite direction, so as to insure that said particles of dirt and metal are dislodged from said interstices or contours. The abrasiveactionsof the respective rotary abrading parts upon the particles or grains in the grinding surface are also in similar opposite directions, whereby a high- 1y effective cleaning, abrading and sharpening action is quickly obtained. v

The abrading wheels are exemplified as having their points of closest approach below their axes of rotation, the axles on which they are mounted drooping laterally preferably from a point preferably in the plane, exemplified by the dotted line cl in Fig. 2, in which the axis of rotation of the grinding wheel and the point of intersection between the lines of contact, extended, between the abrading wheels and the grinding wheel are located, also exemplified as the plane in which the axis of. rotation of the grinding wheel and the axis of the shank of our improved device are located, which has the effect, as exemplified in Fig. 3, of causing the outer edges of the abrading wheels to reach under the grinding wheel to greater extent than the inner edges of said abrading wheels, when grinding or polishing said grinding Wheel on a true cylinder.

The abrading wheels are further mounted on axles having supports at their respective ends, these axles being preferably fixed in their supports, and having ball bearings about said axles adjacent to the respective supports of said axles, the abradi g wheel means of the friction contact of the-rotating grinding wheel :therewith.

We shall describe the niounting of the" abradingl wheel 45, the mounting of the abrading wheel 145 being similar thereto, but having the parts disposed in opposite directions, the parts being designated by similar reference numerals increased to the series .100.

Stubs, shafts or axlesare' provided, here in'atter reterredto as'axles about which the abrading wheels are arranged to-rotate. Re ferring to .Figsul to :5' inclusive, axles 46, 146, are mounted on a: head .47 exemplified as including a plurality of yokes' 48, 148,. comprising outer fork-arms 49, 1&9, and an intermediate fork-ar1n 50, these fork-arms be-' inglaterally arranged. Supports 51, 151,

are located on the outer ends of the outer.

fork-arms, and supports 52, 152, are located at the outer end of the intermediate forkarm. These latter supports may be formed as one andhavetheirsuppor'ting portions for the respective axles extend in angular relation to each other. 7 Caps 53, 153, form releasable parts of the supports on the outer .fOIl{-.fl-I'111S, and are secured to the supporting parts rigid with the fork-arms by bolts '54, 154-. A cap 55'for the intermediate supports '52, 152', is secured to the intermediate fork by bolts 56, this last-namedcap having supporting portions arranged at angular relations to each other for receiving the res ective axles.

The axles are preferably held fixed in their respective supports. Thus they may be clamped firmly in their supports, In order to further avoid relative rotation between the axles we provide'their proximate ends with coacting faces, represented as the end faces 57, 157, which abut each other inthe supports 52, 152, and are at, angles to the respective shafts, whereby relative rotations between the shafts is prevented.

The axles are preferably also held endwise in their supports, as by providing one of their ends with a collar 58, 158, which hold the axles against approach toward each other, such approach being limited by the intermediate supports 52, .152, the other end of the axles. being providedwith shoulders 59, 159, which prevent axial separation between the axles by coaction with the outer supports=51, 151,these latter supports receiving thefreduced ends 60, 160, ofi said axles. Theflpressures on these axles by the grindingwheel is towardithe solid parts'of the supports. r

, Shells 61,161, are received about the axles, ball bearings 62,'162-,beinglocated between the proximate ends. of said shells and axles,

and ball bearings 63, 168, being located be- I tween the outer ends of said shells and axles. 1

Theinner raceways 6 1,164, ofthe inner ball bearings are positioned between the collars 58, 158, on the axles and colla-rs.65,165,

releasably secured to said axles, as by tapered pins 66,166, which may be inserted or removed through holes 67, 167, in the sleeves, normally closed by screws 68, 168.

Helical springs 71, 171, are located between-the collars 65, 165,'and the inner ra'cee wayst72, 172, ofthe outer ball bearings' The outer'r'ace-ways of the proximate ball bearings are located in annular rabb'etsq73, 17 3,.in the inner peripheries of the shells, being held thereinbetween shoulders 74:, 174;,

in said bores and annularflanges 75, 175,011"

said' shells, at the proximate ends of the latter, the said flanges being fixed to said shells by screws 76, 176. Holes 77, 177 a'relin these flanges, thewall s of the holes making close joint with the outer perfipheriessof the collars 58, 158, for-preventing dust and dirt gettinginto the ball bearings and the interior of the shells.

.- The outer raceways 78, 178, of the outer ball'bearings; are located in annular rabbets 79, 179, in" the bores of the shells, and are held between shoulders 80, 180, in said bores and outer end flanges 81, 181, fixed by screws 82, 182, to the outer (ends of said shells. These latter flanges are provided with centralholes 88, 1 83', receivedabout the axles adjacent-to the outer shoulders on saidraxles, and the walls of said holes have close union with said axles for preventing the admission of dust'and dirt into the interior ofthe shells and the ball bearings therein.

The springs 71, 171, are located between the collars 65, 165, and the inner raceways of the outerball bearings about the axles, for normally causing separation between the in nor raceways of the ball bearings at the respective ends of the respective axles. One of the ends of the springs bear against-the collars 65, 165, the other ends of the springs bearing against the inner raceways of the outer ball bearings, for urging the latter axially outward. This causes axial-outward urging of the outer raceways of theouter ball bearings, for causingsiinilar urging of the shells, and consequently of tha outer raceways of the proximate ball bearings, for

ing intimate engagement between the race ways and the balls, and maintaining the shells concentric with said axles, the resistances of the springs being sufficient to prevent axial movements of the shells, which might be due to the lateral stress upon the abrading wheels during operation.

' threaded ends 95, 195, of said shell.

Slight spaces 84, 184, are left between the flanges 81, 181,.and the outer bearings 51, 151, of the yokes. The ball bearings are combined radial and end thrust bearings. The construction maintains the abrading wheels continuously in given paths of rota said shells, between shoulders 93, 193, there-' on and nuts 94:, 194, threaded to the outer Suitable washers 96, 196, preferably fibrous in nature, are located between said abrading wheel, the shoulder and the nut. The threadings of the threaded ends are preferably in such directions as to cause tightening of the nuts during operation of the abrading wheels.-

The axles being normally stationary, they may be of comparatively small diameter, whereby ball bearings of comparatively small diameters may be employed, in order that the holes in the abrading wheels may be of comparatively small diameters,the con-- struction being such, however, that the abrading wheels will withstand great lateral strains, and maintain their paths of rotations truly, as they are provided with a ball bearing and a bearing for the axle at each of their sides, preventing lateral play and wobbling, and enabling comparatively long axles and sleeves to be employed while placing the abrading wheels in angular and close relation to each other for simultaneously acting upon the same grinding wheel in order to true and dress the latter.

The head is provided with a shank 97 extending therefrom, and shown of heavy and substantial nature and arranged to be rigidly secured in place on the grinding machine. I

The exemplified means for fixing the shank in place comprise the following instrumentalities: The table of the grinding or polishing machine is provided with a guide 101 and a rail 102. A clamp 103 is provided with a jaw 104 coacting with the guide and a clamping means, the latter comprising a jaw 106 having an inclined face 107 on the body of the clamp and a clamp-plate 108, the

weaves inclined face and the clamp-plate being arranged to clamp upon the rail 102.

A stem 111 is located in the bearing 112 of the clamp. An adjusting nut 115 and a lock nut 116 are received over the threaded end 117 of said stem. Said stem is provided with a flattened head 119, a fork 120 of ahandle 121 being received about said head and articulated therewith bymeans of a pin 122.

The head 119 is received through a slot in a cap 126. The inner end of the fork 120v is provided with cams 129 and shoulders 130 at the respective sides of the flattened head 119. These cams and shoulders are arranged to bear against the cap, and to cause clamping movement between said cap and the clamp-plate 108 at one side ofthe rail 102 and the inclined fa'ce107 at the other side of said rail, causing clamping of the jaw upon said rail.

The body of the clamp is provided with, a bearing 135, shown as a clamp-bearing, in which the shank 97 is received and rigidly held, the clamp-bearing being clamped to the shank by means'of bolts 136, received through holes of a cheek 138, and threaded in threaded holes of a cheek 140, the cheeks being located at'the respective sides of the split 14:1 in said clamp-bearing, which is thereby constituted a split-bearing. In order to position'the shank rotatively in the clamp, we provide the inner face of the clamp with a groove 142, in which a pin 1 13 in said shank is received. The shank may be axially adjusted in the clamp-bearing. f

The shank is preferably so positioned that its axis is parallel with .ara'dial line of the grinding wheel, as indicated by the dotted line (Z, and so that each of the abrading wheels will be inclined equally with relation to a plane perpendicular to the axis of the grinding wheel. This inclining may be'exemplified as a drooping inclination of five degrees from the perpendicular for each'of the abrading wheels.

One or, both of the abrading wheels may be employed, both being employed preferably when grinding wheels having comparatively wide faces are to be true d or dressed, so that the truing and dressing operation may be perforn'ied before detrimental wear sets in in the abrading wheels, in order that a truly cylindrical grinding wheel having an even surface throughout may result from the employment of the abrading wheels.

If it is desired to employ one of the abrading wheels, a structure like the modification shown in Figs. 6 to 8 inclusive may be employed, in which parts simila-r'to the parts shown and described in Figs. 1 to 5 inelusive, are identified by similar reference numerals, raised to the series 200. V

In this modification, the axle 246 has its respective ends mounted in supports 251, 252,

of the abrading wheels 45, 145, to said" grinding wheel. The shank 297 may be axially adjusted in said bearing 135. p

Our improved device provides ready, simple, strong and accurate means for obtaining quick and efiective truing, dressing, cleaning and sharpening of the grinding wheel in novel manner, and when employing a plurality of abrading wheels acting simultaneously on the grinding wheel, the abrading wheels act with a cross-wiping motion in paths which cross each other upon the surface of the grinding wheel in highly effestive manner, the lateral stresses of the grinding wheel upon the abrading wheels being counteracted by ball-bearings and yoke supports at the respective sides of each of the abrading wheels. 5

Having thus fully described our invention, what we claimas new, and desire to secure by Letters Patent, is':

In mechanism for truing and dressing grinding wheels, the combination of a head comprising a pair of outer fork-arms and an intermediate fork-arm complemental to said respective outer'fork-arms and forming a pair of yokes having an integral intermediate fork-arnrwhich is common to both said yokes, an axle for each of said yokes, each of said outer fork-arms comprising a supporting portion at its outer end, a releasable cap for each of said supporting portions, said intermediate fork-arm comprising an intermediatejduplex supporting portion at its outer end, a releasable intermediate. duplex cap for said intermediate duplex supporting portion, said axles located in non-parallel endwise relation, the outer ends of said axles located in said first-named supporting portions and clamped in place by said first-named releasable caps, and the inner ends of both said axles located in said intermediate duplex supporting portion and clamped in place by said duplex cap, each of said axles provided with shoulders at its respective ends coacting respectively with said outer supporting portions and said intermediate duplex supporting portion for endwise positioning of said axles, and the proximate ends of said axles provided with parallel abutting end faces having opposite inclinations fromfthe same sides'of said respective axles and of the same degree to thelongitudinal' axes of said respective axles and coacting with each other for resisting rotations of bothsaid axles, and abrading wheels rotatable about said respective axles. In testimony whereof, we have hereunto signed our names.

FERDINAND J. HOHNHORST. J

' FERDINAND J. KBOEGER. 

